Humans and animals can be exposed to mixtures of chemicals from food and water, especially during disasters such as extended droughts, hurricanes and floods. Drought stress facilitates the occurrence of mycotoxins such as aflatoxins B₁ (AfB₁) and zearalenone (ZEN), while hurricanes and floods can mobilize toxic soil and sediments containing important pesticides (such as glyphosate). To address this problem in food, feed and water, we developed broad-acting, clay-based enterosorbents that can reduce toxin exposures when included in the diet. In this study, we processed sodium and calcium montmorillonite clays with high concentrations of sulfuric acid to increase surface areas and porosities, and conducted equilibrium isothermal analyses and dosimetry studies to derive binding parameters and gain insight into: (1) surface capacities and affinities, (2) potential mechanisms of sorption, (3) thermodynamics (enthalpy) of toxin/surface interactions and (4) estimated dose of sorbent required to maintain toxin threshold limits. We have also used a toxin-sensitive living organism (Hydra vulgaris) to predict the safety and efficacy of newly developed sorbents. Our results indicated that acid processed montmorillonites were effective sorbents for AfB₁, ZEN and glyphosate, with high capacity and tight binding, and effectively protected hydra against individual toxins, as well as mixtures of mycotoxins.

An on-line system employing switchable-hydrophilicity solvent-based liquid-phase microextraction (SHS-LPME) is described in this work. The method is based on the preconcentration of the species formed between cobalt and the reagent 1-nitroso-2-naphthol (NN), with subsequent detection by digital image colorimetry. The system's operation begins with the on-line mixture of sample, switchable solvent, and an alkaline agent in a reaction coil. Then the mixture is transported to an extraction chamber. The introduction of a proton donor leads to the passage of the solvent to its hydrophobic form, which allows phase separation. The rich phase is then directed to a glass tube, where detection is performed. Octanoic acid, sodium carbonate, and sulfuric acid were used as the extraction solvent, the alkaline agent, and the proton donor, respectively. Under optimized conditions, the method presented a detection limit of 0.8 μg L⁻¹ and an enrichment factor of 41. The precision obtained was 4.8% (20 μg L⁻¹). The accuracy of the method was tested by the analysis of Tomato Leaves certified reference material (NIST 1573a). The method was applied to the determination of cobalt in food, dietary supplements, and water samples. The method is presented as a green alternative and very accessible to the determination of cobalt in the analyzed samples.